Diallel analysis, maternal effect and heritability in groundnut for yield components and oil content

Groundnut is one of the world's major food and oil crops. Being sources of nutrition and vegetable oil, rich in affordable and digestible protein, it is a strategic crop in Burkina Faso for food security, nutrition, and cash income. Understanding the nature of gene effect and genetic variation affecting yield and yield component traits will contribute to designing appropriate breeding methods for groundnut improvement and increase selection efficiency in Burkina Faso.

In 2018, a total of 30 F₂ progenies were generated through a 6 x 6 full diallel mating using six different and contrasting varieties. In 2019, parents and progenies were evaluated in a lattice square design in 3 replications at ICRISAT-Mali experimental field to assess the general combining ability (GCA) and specific combining ability (SCA) effects, the inheritance and the maternal and reciprocal effects for yield component traits (YCT) and oil content (OC).

Significant variabilities were observed among the parental genotypes and their F₂ progenies for DTH, PSR, HPW, PL, PWD, SL, SWD, and OAC. Mean performance of the six parents were HPW (117.05g), HSW (57.24 g), PYH (1914.76), SYH (1312.73), PL (2.52), PWD (1,19), SL (1.38), SWD (0.83), OC (49.43), OAC (50.43) and LAC (33.61). Parent QH243C presented the highest value for SWD (1.02 cm) and OAC (60.76) while the parent ICGV09195 had the highest value of OC (50.36). Chalimbana presented the highest value of HPW (169.61 g), PL (2.98 cm), PWD (1. 41 cm), and SL (1.57 cm) while CG7 presented the highest value for HSW (75. 14 g), and SYH (1639.28 kg). Both YCT and OC are controlled by additive and non-additive gene effects with a predominance of additive gene action for HSW, SL, and SWD, whereas HPW, PL, PWD, and OAC were found to be more controlled by non-additive gene effects. Maternal effects as well as nuclear and cytoplasmic interaction effects were observed for both YCT and OC indicating that YCT and OC are influenced by a combination of genetic factors from both the maternal parent and the nuclear genome, as well as cytoplasmic factors such as mitochondrial DNA. Broad sense heritability ranged from 3.76 % to 91.56 %, and higher broad sense heritability values were recorded for pod length (91.56 %), hundred pod weight (83.71 %) and pod width (80.95 %).

The study yields valuable insights into the inheritance of YCT and OC. The parents, Chalimbana and CG7, showed promise as good combiners for both yield component traits and oil content when used as male parents while TE3, Sh470P and QH243C can be used as female for the oil content and its components (oleic and linoleic content).